* XFS WARN_ON in xfs_vm_writepage @ 2014-06-13 5:16 Dave Jones 2014-06-13 6:26 ` Dave Chinner 0 siblings, 1 reply; 6+ messages in thread From: Dave Jones @ 2014-06-13 5:16 UTC (permalink / raw) To: xfs; +Cc: Linux Kernel Just hit this on Linus' tree from earlier this afternoon.. WARNING: CPU: 3 PID: 19721 at fs/xfs/xfs_aops.c:971 xfs_vm_writepage+0x5ce/0x630 [xfs]() CPU: 3 PID: 19721 Comm: trinity-c61 Not tainted 3.15.0+ #3 0000000000000009 000000004f70ab82 ffff8801d5ebf578 ffffffff8373215c 0000000000000000 ffff8801d5ebf5b0 ffffffff8306f7cd ffff88023dd543e0 ffffea000254a3c0 ffff8801d5ebf820 ffffea000254a3e0 ffff8801d5ebf728 Call Trace: [<ffffffff8373215c>] dump_stack+0x4e/0x7a [<ffffffff8306f7cd>] warn_slowpath_common+0x7d/0xa0 [<ffffffff8306f8fa>] warn_slowpath_null+0x1a/0x20 [<ffffffffc023068e>] xfs_vm_writepage+0x5ce/0x630 [xfs] [<ffffffff8373f1ab>] ? preempt_count_sub+0xab/0x100 [<ffffffff83347315>] ? __percpu_counter_add+0x85/0xc0 [<ffffffff8316f759>] shrink_page_list+0x8f9/0xb90 [<ffffffff83170123>] shrink_inactive_list+0x253/0x510 [<ffffffff83170c93>] shrink_lruvec+0x563/0x6c0 [<ffffffff83170e2b>] shrink_zone+0x3b/0x100 [<ffffffff831710e1>] shrink_zones+0x1f1/0x3c0 [<ffffffff83171414>] try_to_free_pages+0x164/0x380 [<ffffffff83163e52>] __alloc_pages_nodemask+0x822/0xc90 [<ffffffff83169eb2>] ? pagevec_lru_move_fn+0x122/0x140 [<ffffffff831abeff>] alloc_pages_vma+0xaf/0x1c0 [<ffffffff8318a931>] handle_mm_fault+0xa31/0xc50 [<ffffffff831845c0>] ? follow_page_mask+0x1f0/0x320 [<ffffffff8318491b>] __get_user_pages+0x22b/0x660 [<ffffffff831b5093>] ? kmem_cache_alloc+0x183/0x210 [<ffffffff8318ce7e>] __mlock_vma_pages_range+0x9e/0xd0 [<ffffffff8318d6ba>] __mm_populate+0xca/0x180 [<ffffffff83179033>] vm_mmap_pgoff+0xd3/0xe0 [<ffffffff8318fbd6>] SyS_mmap_pgoff+0x116/0x2c0 [<ffffffff83011ced>] ? syscall_trace_enter+0x14d/0x2a0 [<ffffffff830084c2>] SyS_mmap+0x22/0x30 [<ffffffff837436ef>] tracesys+0xdd/0xe2 970 if (WARN_ON_ONCE((current->flags & (PF_MEMALLOC|PF_KSWAPD)) == 971 PF_MEMALLOC)) ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: XFS WARN_ON in xfs_vm_writepage 2014-06-13 5:16 XFS WARN_ON in xfs_vm_writepage Dave Jones @ 2014-06-13 6:26 ` Dave Chinner 2014-06-13 14:19 ` Dave Jones 0 siblings, 1 reply; 6+ messages in thread From: Dave Chinner @ 2014-06-13 6:26 UTC (permalink / raw) To: Dave Jones, xfs, Linux Kernel; +Cc: linux-mm [cc linux-mm] On Fri, Jun 13, 2014 at 01:16:31AM -0400, Dave Jones wrote: > Just hit this on Linus' tree from earlier this afternoon.. > > WARNING: CPU: 3 PID: 19721 at fs/xfs/xfs_aops.c:971 xfs_vm_writepage+0x5ce/0x630 [xfs]() > CPU: 3 PID: 19721 Comm: trinity-c61 Not tainted 3.15.0+ #3 > 0000000000000009 000000004f70ab82 ffff8801d5ebf578 ffffffff8373215c > 0000000000000000 ffff8801d5ebf5b0 ffffffff8306f7cd ffff88023dd543e0 > ffffea000254a3c0 ffff8801d5ebf820 ffffea000254a3e0 ffff8801d5ebf728 > Call Trace: > [<ffffffff8373215c>] dump_stack+0x4e/0x7a > [<ffffffff8306f7cd>] warn_slowpath_common+0x7d/0xa0 > [<ffffffff8306f8fa>] warn_slowpath_null+0x1a/0x20 > [<ffffffffc023068e>] xfs_vm_writepage+0x5ce/0x630 [xfs] > [<ffffffff8373f1ab>] ? preempt_count_sub+0xab/0x100 > [<ffffffff83347315>] ? __percpu_counter_add+0x85/0xc0 > [<ffffffff8316f759>] shrink_page_list+0x8f9/0xb90 > [<ffffffff83170123>] shrink_inactive_list+0x253/0x510 > [<ffffffff83170c93>] shrink_lruvec+0x563/0x6c0 > [<ffffffff83170e2b>] shrink_zone+0x3b/0x100 > [<ffffffff831710e1>] shrink_zones+0x1f1/0x3c0 > [<ffffffff83171414>] try_to_free_pages+0x164/0x380 > [<ffffffff83163e52>] __alloc_pages_nodemask+0x822/0xc90 > [<ffffffff83169eb2>] ? pagevec_lru_move_fn+0x122/0x140 > [<ffffffff831abeff>] alloc_pages_vma+0xaf/0x1c0 > [<ffffffff8318a931>] handle_mm_fault+0xa31/0xc50 > [<ffffffff831845c0>] ? follow_page_mask+0x1f0/0x320 > [<ffffffff8318491b>] __get_user_pages+0x22b/0x660 > [<ffffffff831b5093>] ? kmem_cache_alloc+0x183/0x210 > [<ffffffff8318ce7e>] __mlock_vma_pages_range+0x9e/0xd0 > [<ffffffff8318d6ba>] __mm_populate+0xca/0x180 > [<ffffffff83179033>] vm_mmap_pgoff+0xd3/0xe0 > [<ffffffff8318fbd6>] SyS_mmap_pgoff+0x116/0x2c0 > [<ffffffff83011ced>] ? syscall_trace_enter+0x14d/0x2a0 > [<ffffffff830084c2>] SyS_mmap+0x22/0x30 > [<ffffffff837436ef>] tracesys+0xdd/0xe2 > > > 970 if (WARN_ON_ONCE((current->flags & (PF_MEMALLOC|PF_KSWAPD)) == > 971 PF_MEMALLOC)) What were you running at the time? The XFS warning is there to indicate that memory reclaim is doing something it shouldn't (i.e. dirty page writeback from direct reclaim), so this is one for the mm folk to work out... Cheers, Dave. -- Dave Chinner david@fromorbit.com ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: XFS WARN_ON in xfs_vm_writepage 2014-06-13 6:26 ` Dave Chinner @ 2014-06-13 14:19 ` Dave Jones 2014-06-19 2:03 ` Dave Chinner 0 siblings, 1 reply; 6+ messages in thread From: Dave Jones @ 2014-06-13 14:19 UTC (permalink / raw) To: Dave Chinner; +Cc: xfs, Linux Kernel, linux-mm On Fri, Jun 13, 2014 at 04:26:45PM +1000, Dave Chinner wrote: > > 970 if (WARN_ON_ONCE((current->flags & (PF_MEMALLOC|PF_KSWAPD)) == > > 971 PF_MEMALLOC)) > > What were you running at the time? The XFS warning is there to > indicate that memory reclaim is doing something it shouldn't (i.e. > dirty page writeback from direct reclaim), so this is one for the mm > folk to work out... Trinity had driven the machine deeply into swap, and the oom killer was kicking in pretty often. Then this happened. Dave ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: XFS WARN_ON in xfs_vm_writepage 2014-06-13 14:19 ` Dave Jones @ 2014-06-19 2:03 ` Dave Chinner 2014-06-23 20:27 ` Dave Jones 0 siblings, 1 reply; 6+ messages in thread From: Dave Chinner @ 2014-06-19 2:03 UTC (permalink / raw) To: Dave Jones, xfs, Linux Kernel, linux-mm On Fri, Jun 13, 2014 at 10:19:25AM -0400, Dave Jones wrote: > On Fri, Jun 13, 2014 at 04:26:45PM +1000, Dave Chinner wrote: > > > > 970 if (WARN_ON_ONCE((current->flags & (PF_MEMALLOC|PF_KSWAPD)) == > > > 971 PF_MEMALLOC)) > > > > What were you running at the time? The XFS warning is there to > > indicate that memory reclaim is doing something it shouldn't (i.e. > > dirty page writeback from direct reclaim), so this is one for the mm > > folk to work out... > > Trinity had driven the machine deeply into swap, and the oom killer was > kicking in pretty often. Then this happened. Yup, sounds like a problem somewhere in mm/vmscan.c.... Cheers, Dave. -- Dave Chinner david@fromorbit.com ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: XFS WARN_ON in xfs_vm_writepage 2014-06-19 2:03 ` Dave Chinner @ 2014-06-23 20:27 ` Dave Jones 2014-06-24 1:02 ` Dave Chinner 0 siblings, 1 reply; 6+ messages in thread From: Dave Jones @ 2014-06-23 20:27 UTC (permalink / raw) To: Dave Chinner; +Cc: xfs, Linux Kernel, linux-mm On Thu, Jun 19, 2014 at 12:03:40PM +1000, Dave Chinner wrote: > On Fri, Jun 13, 2014 at 10:19:25AM -0400, Dave Jones wrote: > > On Fri, Jun 13, 2014 at 04:26:45PM +1000, Dave Chinner wrote: > > > > > > 970 if (WARN_ON_ONCE((current->flags & (PF_MEMALLOC|PF_KSWAPD)) == > > > > 971 PF_MEMALLOC)) > > > > > > What were you running at the time? The XFS warning is there to > > > indicate that memory reclaim is doing something it shouldn't (i.e. > > > dirty page writeback from direct reclaim), so this is one for the mm > > > folk to work out... > > > > Trinity had driven the machine deeply into swap, and the oom killer was > > kicking in pretty often. Then this happened. > > Yup, sounds like a problem somewhere in mm/vmscan.c.... I'm now hitting this fairly often, and no-one seems to have offered up any suggestions yet, so I'm going to flail and guess randomly until someone has a better idea what could be wrong. That WARN commentary for the benefit of linux-mm readers.. 960 /* 961 * Refuse to write the page out if we are called from reclaim context. 962 * 963 * This avoids stack overflows when called from deeply used stacks in 964 * random callers for direct reclaim or memcg reclaim. We explicitly 965 * allow reclaim from kswapd as the stack usage there is relatively low. 966 * 967 * This should never happen except in the case of a VM regression so 968 * warn about it. 969 */ 970 if (WARN_ON_ONCE((current->flags & (PF_MEMALLOC|PF_KSWAPD)) == 971 PF_MEMALLOC)) 972 goto redirty; Looking at this trace.. xfs_vm_writepage+0x5ce/0x630 [xfs] ? preempt_count_sub+0xab/0x100 ? __percpu_counter_add+0x85/0xc0 shrink_page_list+0x8f9/0xb90 shrink_inactive_list+0x253/0x510 shrink_lruvec+0x563/0x6c0 shrink_zone+0x3b/0x100 shrink_zones+0x1f1/0x3c0 try_to_free_pages+0x164/0x380 __alloc_pages_nodemask+0x822/0xc90 alloc_pages_vma+0xaf/0x1c0 read_swap_cache_async+0x123/0x220 ? final_putname+0x22/0x50 swapin_readahead+0x149/0x1d0 ? find_get_entry+0xd5/0x130 ? pagecache_get_page+0x30/0x210 ? debug_smp_processor_id+0x17/0x20 handle_mm_fault+0x9d5/0xc50 __do_page_fault+0x1d2/0x640 ? __acct_update_integrals+0x8b/0x120 ? preempt_count_sub+0xab/0x100 do_page_fault+0x1e/0x70 page_fault+0x22/0x30 The reclaim here looks to be triggered from the readahead code. Should something in that path be setting PF_KSWAPD in the gfp mask ? Dave ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: XFS WARN_ON in xfs_vm_writepage 2014-06-23 20:27 ` Dave Jones @ 2014-06-24 1:02 ` Dave Chinner 0 siblings, 0 replies; 6+ messages in thread From: Dave Chinner @ 2014-06-24 1:02 UTC (permalink / raw) To: Dave Jones, xfs, Linux Kernel, linux-mm On Mon, Jun 23, 2014 at 04:27:14PM -0400, Dave Jones wrote: > On Thu, Jun 19, 2014 at 12:03:40PM +1000, Dave Chinner wrote: > > On Fri, Jun 13, 2014 at 10:19:25AM -0400, Dave Jones wrote: > > > On Fri, Jun 13, 2014 at 04:26:45PM +1000, Dave Chinner wrote: > > > > > > > > 970 if (WARN_ON_ONCE((current->flags & (PF_MEMALLOC|PF_KSWAPD)) == > > > > > 971 PF_MEMALLOC)) > > > > > > > > What were you running at the time? The XFS warning is there to > > > > indicate that memory reclaim is doing something it shouldn't (i.e. > > > > dirty page writeback from direct reclaim), so this is one for the mm > > > > folk to work out... > > > > > > Trinity had driven the machine deeply into swap, and the oom killer was > > > kicking in pretty often. Then this happened. > > > > Yup, sounds like a problem somewhere in mm/vmscan.c.... > > I'm now hitting this fairly often, and no-one seems to have offered up > any suggestions yet, so I'm going to flail and guess randomly until someone > has a better idea what could be wrong. You are not alone - I haven't been able to get anyone from the MM side of things to comment on any of the bad behaviours we've had reported recently. > That WARN commentary for the benefit of linux-mm readers.. > > 960 /* > 961 * Refuse to write the page out if we are called from reclaim context. > 962 * > 963 * This avoids stack overflows when called from deeply used stacks in > 964 * random callers for direct reclaim or memcg reclaim. We explicitly > 965 * allow reclaim from kswapd as the stack usage there is relatively low. > 966 * > 967 * This should never happen except in the case of a VM regression so > 968 * warn about it. > 969 */ > 970 if (WARN_ON_ONCE((current->flags & (PF_MEMALLOC|PF_KSWAPD)) == > 971 PF_MEMALLOC)) > 972 goto redirty; > > > Looking at this trace.. > > xfs_vm_writepage+0x5ce/0x630 [xfs] > ? preempt_count_sub+0xab/0x100 > ? __percpu_counter_add+0x85/0xc0 > shrink_page_list+0x8f9/0xb90 > shrink_inactive_list+0x253/0x510 > shrink_lruvec+0x563/0x6c0 > shrink_zone+0x3b/0x100 > shrink_zones+0x1f1/0x3c0 > try_to_free_pages+0x164/0x380 > __alloc_pages_nodemask+0x822/0xc90 > alloc_pages_vma+0xaf/0x1c0 > read_swap_cache_async+0x123/0x220 > ? final_putname+0x22/0x50 > swapin_readahead+0x149/0x1d0 > ? find_get_entry+0xd5/0x130 > ? pagecache_get_page+0x30/0x210 > ? debug_smp_processor_id+0x17/0x20 > handle_mm_fault+0x9d5/0xc50 > __do_page_fault+0x1d2/0x640 > ? __acct_update_integrals+0x8b/0x120 > ? preempt_count_sub+0xab/0x100 > do_page_fault+0x1e/0x70 > page_fault+0x22/0x30 > > The reclaim here looks to be triggered from the readahead code. > Should something in that path be setting PF_KSWAPD in the gfp mask ? Definitely not. It's not kswapd that is doing the memory allocation and we most certainly do not want direct reclaim to get a free pass through reclaim congestion and backoff algorithms. This could be another symptom of the other problems we've been seeing which involve direct reclaim thottling way too hard (via the too_many_isolated() loops) and getting stuck. This is a case of direct reclaim finding dirty pages on the LRU, which should have been handled by writeback threads or kswapd before direct reclaim can find them. IOWs, direct reclaim is doing work when it probably should have been throttled. As the comment in the XFS code says: "This should never happen except in the case of a VM regression..." Cheers, Dave. -- Dave Chinner david@fromorbit.com ^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2014-06-24 1:07 UTC | newest] Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2014-06-13 5:16 XFS WARN_ON in xfs_vm_writepage Dave Jones 2014-06-13 6:26 ` Dave Chinner 2014-06-13 14:19 ` Dave Jones 2014-06-19 2:03 ` Dave Chinner 2014-06-23 20:27 ` Dave Jones 2014-06-24 1:02 ` Dave Chinner
This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for NNTP newsgroup(s).